要获得所有已安装的应用程序，您可以使用包管理器

List<PackageInfo> apps = getPackageManager().getInstalledPackages(0);

要运行一个应用程序，你可以使用它的包名

Intent launchApp = getPackageManager().getLaunchIntentForPackage(“package name”)
startActivity(launchApp);

欲了解更多细节，请阅读这个博客http://codebucket.co.in/android-get-list-of-all-installed-apps/

你可以通过下面的代码找到Android设备中已安装的应用程序列表，“packageInfo”包含已安装的应用程序信息 在设备。我们可以为安装的应用程序检索Intent packageinfo对象可以使用startactivity(intent)来启动 应用程序。这取决于你如何组织UI或Listview 或显示数据表格。基于位置的点击事件，你可以检索意图 对象和启动活动意图。

final PackageManager pm = getPackageManager();

List<ApplicationInfo> packages = pm.getInstalledApplications(PackageManager.GET_META_DATA);


for (ApplicationInfo packageInfo : packages) 

{
 if(pm.getLaunchIntentForPackage(packageInfo.packageName)!= null &&   

                   !pm.getLaunchIntentForPackage(packageInfo.packageName).equals(""))


{

    System.out.println("Package Name :" + packageInfo.packageName);

    System.out.println("Launch Intent For Package :"   +  
                  pm.getLaunchIntentForPackage(packageInfo.packageName));

    System.out.println("Application Label :"   + pm.getApplicationLabel(packageInfo));

    System.out.println("Application Label :"   + 
                           pm.getApplicationIcon(packageInfo.packageName).toString());

    System.out.println("i : "+i);

    /*if(i==2)

    {
         startActivity(pm.getLaunchIntentForPackage(packageInfo.packageName));

     break;

    }*/

    i++;

}
}

下面是使用PackageManager的一种更简洁的方式

final PackageManager pm = getPackageManager();
//get a list of installed apps.
List<ApplicationInfo> packages = pm.getInstalledApplications(PackageManager.GET_META_DATA);

for (ApplicationInfo packageInfo : packages) {
    Log.d(TAG, "Installed package :" + packageInfo.packageName);
    Log.d(TAG, "Source dir : " + packageInfo.sourceDir);
    Log.d(TAG, "Launch Activity :" + pm.getLaunchIntentForPackage(packageInfo.packageName)); 
}
// the getLaunchIntentForPackage returns an intent that you can use with startActivity() 

更多信息请点击这里http://qtcstation.com/2011/02/how-to-launch-another-app-from-your-app/

public static List<ApplicationInfo> getApplications(Context context) {
    return context.getPackageManager().getInstalledApplications(PackageManager.GET_META_DATA);
}

过滤基于系统的应用程序:

private boolean isSystemPackage(ResolveInfo ri) {
    return (ri.activityInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0;
}

这里有一个很好的例子:

class PInfo {
    private String appname = "";
    private String pname = "";
    private String versionName = "";
    private int versionCode = 0;
    private Drawable icon;
    private void prettyPrint() {
        Log.v(appname + "\t" + pname + "\t" + versionName + "\t" + versionCode);
    }
}

private ArrayList<PInfo> getPackages() {
    ArrayList<PInfo> apps = getInstalledApps(false); /* false = no system packages */
    final int max = apps.size();
    for (int i=0; i<max; i++) {
        apps.get(i).prettyPrint();
    }
    return apps;
}

private ArrayList<PInfo> getInstalledApps(boolean getSysPackages) {
    ArrayList<PInfo> res = new ArrayList<PInfo>();        
    List<PackageInfo> packs = getPackageManager().getInstalledPackages(0);
    for(int i=0;i<packs.size();i++) {
        PackageInfo p = packs.get(i);
        if ((!getSysPackages) && (p.versionName == null)) {
            continue ;
        }
        PInfo newInfo = new PInfo();
        newInfo.appname = p.applicationInfo.loadLabel(getPackageManager()).toString();
        newInfo.pname = p.packageName;
        newInfo.versionName = p.versionName;
        newInfo.versionCode = p.versionCode;
        newInfo.icon = p.applicationInfo.loadIcon(getPackageManager());
        res.add(newInfo);
    }
    return res; 
}